An image output apparatus such as a game console or a DVD player that generates and outputs a video or an image is used in a state of being connected to an image display apparatus such as a liquid crystal television, a personal computer display or a game console display. The ratio of vertical length and horizontal length of a screen in a front view of such an image display apparatus (hereinafter, referred to as an aspect ratio) is not consistent. Particularly, it is known that aspect ratios of screens of mobile terminal devices such as smart phones or tablet terminals are different according to model type.
When the ratio of the vertical length and the horizontal length of an image which is an output target is different from an aspect ratio of an image display apparatus, an output method based on a letterboxing scheme, a squeezing scheme or the like, or a method of adjusting and displaying the image to correspond to the aspect ratio of the image display apparatus using a program is widely used. For example, a method of determining the type of an apparatus that outputs an image and changing the image to be output according to the type of a display (for example, see JP2002-221955A), or a method of prescribing a division pattern for dividing a display screen of an image display apparatus into plural areas in association with an aspect ratio of the display screen to output an image without collapsing the content of the image with respect to an image display apparatus having a different aspect ratio (for example, see JP2006-106371A) is used.